Measurement instrument, reagent carrier used for the same, information recorded medium, measurement data correcting method, and program recorded medium

ABSTRACT

A measurement instrument for adequately correcting data in consideration of the deterioration with time of a reagent used for measurement. A deterioration correction data table where the variation of the sensitivity of each reagent from the date of manufacture of the reagent to the expiration date is recorded for each lot is stored in a deterioration correction data storage unit ( 3   b ). A bar code including information designating the lot and the data of manufacture is attached to the reagent. A CPU ( 1 ) designates the deterioration correction data table corresponding to the lot of the reagent used for measurement according to the reagent information read by the bar code reader of a nozzle drive unit ( 10 ), calculates the reagent sensitivity by interpolation on the measurement date with reference to the designated deterioration data table, and corrects the measurement data with respect to the deterioration of the reagent according to the calculated reagent sensitivity.

TECHNICAL FIELD

The present invention relates to a measurement instrument and ameasurement method for measuring a specific component in a body fluid(specimen) such as blood, urine, etc. by using a reagent cartridge inwhich a liquid reagent is filled in advance, a test piece, and the like.More specifically, the present invention relates to a measurementinstrument and a measurement method for adequately correcting data inaccordance with the deterioration of a reagent over time.

BACKGROUND ART

Conventionally, in particular, in the field of the clinical examination,a known measurement instrument includes a measurement instrument forreacting a specimen such as human blood, urine, etc., with a reagent,and measuring, for example, the change of the absorbance of the reagent,thereby determining a specific component in the specimen.

As such a conventional measurement instrument, an instrument using adisposable reagent is known. The disposable reagent can be classifiedinto a cartridge type reagent in which a liquid reagent is filled in acontainer (hereinafter, “a reagent cartridge” will be referred to) and atest piece, that is, a so-called dry reagent.

The test piece is allowed to carry a reagent by impregnating a filterpaper or sheet resin, etc., or by forming a reagent layer on a basematerial. Before reacting with a specimen, the test piece is in a drystate or in a substantially dry state (at least not in a liquid state).That's why the test piece is referred to as a dry reagent.

On the other hand, the reagent cartridge, which has a plurality ofchambers into which necessary reagents, etc. are dispensed in accordancewith items to be measured, is supplied in a state in which it is sealedby measurement instrument makers, reagent makers, etc. At the time ofmeasurement, when a specimen is filled in a specimen chamber of thereagent cartridge and then the reagent cartridge is set in themeasurement instrument, the measurement instrument, for example,automatically mixes the specimen with the reagent, and carries out themeasurement.

A conventional measurement instrument corrects the reagent sensitivitybefore measurement by taking the deterioration of a reagent over timeand a difference of a reagent between lots into account. That is, everytime a user of the measurement instrument purchases a new lot of reagentcartridge or test piece, the user carries out the work includingmeasuring a material having a known concentration by using the purchasedreagent cartridge or the test piece, thereby forming a calibration curvefor each lot of the reagent cartridge or the test piece, and storing itin the instrument.

In general, the user carries out a measurement of two kinds ofmaterials, that is, a high concentration standard liquid and a lowconcentration standard liquid, forms a calibration curve as a linearexpression by connecting both measurement values, and stores the formedcalibration curve in a recording medium such as a magnetic card that canbe read by the measurement instrument. This work takes a lot of time andlabor. Therefore, in many cases, makers of a reagent cartridge or testpiece manufacture a recording medium in which information of acalibration curve is stored for each lot and ship the above-mentionedrecording medium together with the reagent cartridge or the test pieceby attaching it on the reagent cartridge or the test piece.

However, as mentioned above, since the conventional measurementinstrument carries out the linear expression correction by a calibrationcurve, there have been problems in that it is difficult to carry out anadequate correction in accordance with the difference between lots of areagent, and that in the case where the reagent sensitivity inaccordance with the deterioration over time changes non-linearly, anadequate correction cannot be carried out.

DISCLOSURE OF THE INVENTION

In order to solve these problems, it is an object of the presentinvention to provide a measurement instrument for adequately correctingdata in accordance with the difference between lots and thedeterioration of a reagent over time used for measurement.

In order to achieve the above-mentioned object, the measurementinstrument of the present invention carries out a measurement by using areagent carrier that carries a reagent in accordance with items to bemeasured, and carries out a deterioration correction of the measurementdata in accordance with the deterioration of the reagent used formeasurement over time. To the reagent carrier, an information indicator,in which reagent information including information necessary todesignate the lot and the date of manufacture is recorded, is attached.The measurement instrument includes a deterioration correction datastorage unit for storing a deterioration correction data table showingthe situation of the deterioration over time from the date ofmanufacture to the expiration date by the deterioration indices atplural points on a time series for each lot of the reagent carrier; anindicator reading unit for reading the reagent information from theinformation indicator attached to the reagent carrier to be measured; ameasurement date obtaining unit for obtaining the measurement date whenthe measurement is executed; and a measurement controlling unit fordesignating the deterioration correction data table corresponding to thelot of the reagent carrier to be measured with reference to thedeterioration correction data storage unit based on the reagentinformation read by the indicator reading unit, calculating adeterioration index by interpolation at the measurement date based onthe deterioration indices at the preceding point and the following pointof the measurement date among deterioration indices recorded in thedesignated deterioration correction data table, and carrying out thedeterioration correction of the measurement data based on the calculateddeterioration index.

According to this configuration, the deterioration correction data tableis stored in the deterioration correction data storage unit. Thedeterioration correction data table shows the situation of thedeterioration over time from the date of manufacture to the expirationdate as the deterioration indices at plural points on a time series foreach lot of the reagent carrier. The information reading unit reads outthe reagent information including the information necessary to designatethe lot and the date of manufacture of the reagent carrier. Themeasurement controlling unit designates the deterioration correctiondata table corresponding to the lot of the reagent carrier used formeasurement. Note here that as the deterioration index in thedeterioration correction data table, for example, the numericallyrepresented reagent sensitivity can be used.

Furthermore, the measurement controlling unit designates two consecutivepoints corresponding to the preceding point and the following point ofthe measurement date among the deterioration indices at plural pointsrecorded on a time series, calculates the deterioration index at themeasurement date by interpolation from the deterioration indices atthese two points, and carries out the deterioration correction of themeasurement data based on the calculated deterioration index.

Thus, even if the deterioration index over time changes non-linearly, itis possible to calculate the deterioration index of a reagent at themeasurement date exactly. Furthermore, since the deteriorationcorrection data table is provided for each lot of the reagent carrier,it is possible to solve the difference of the reagent sensitivities,etc. between lots. As a result, it is possible to provide a measurementinstrument capable of obtaining the measurement data adequatelycorrected in accordance with the deterioration over time and thedifference between lots of a reagent without the need for thecalibration before measurement.

In the above-mentioned measurement instrument, it is preferable that themeasurement controlling unit derives a deterioration index calculationexpression that satisfies the deterioration indices at two points basedon an earlier point of the two points, calculates the number of daysfrom the earlier point of the two points to the measurement date, andsubstitutes the number of days in the deterioration index calculationexpression, thereby calculating the deterioration index at themeasurement date. Thus, it is possible to calculate the deteriorationindex at the measurement date exactly.

In the measurement instrument with preferred configuration, it ispreferable that the deterioration index calculation expression is alinear expression. Thus, it is possible to derive the deteriorationindex calculation expression by a simple calculation.

It is preferable that the measurement instrument further includes aninformation reading unit for reading information from an informationrecorded medium, using the information recorded medium in which thedeterioration information representing the situation of thedeterioration over time from the date of manufacture to the expirationdate for each lot of the reagent carrier, reading the deteriorationinformation from the information recorded medium by the informationreading unit, forming the deterioration correction data table based onthe read deterioration information, and storing it in the deteriorationcorrection data storage unit.

According to this configuration, with a simple operation of allowing theinformation recording unit to read the information recorded medium, thedeterioration correction data table of the reagent carrier used formeasurement can be stored in the deterioration correction data storageunit. Note here that this information recorded medium can be supplied toa user of the measurement instrument in a way in which, for example, amaker etc. of a reagent carrier, at the time of manufacture, forms theinformation recorded medium for each lot of the reagent carrier andattaches it on the manufactured reagent carrier and ships theinformation recorded medium together with the measurement carrier.

In the measurement instrument, the deterioration information recorded inthe information recorded medium is a differential data table showing thedifference between the deterioration index at each point and thedeterioration index at the preceding point of the point with respect toplural points from the date of manufacture to the expiration date. Thus,as compared with the case where the deterioration correction data tableitself is recorded as the deterioration information, it is advantageousthat the volume of the deterioration information to be recorded in theinformation recorded medium may be small.

In the measurement instrument, it is further preferable that thedeterioration information recorded in the information recorded medium isthe deterioration correction data table. Thus, it is possible to storethe deterioration correction data table in the measurement instrument bya simple process of copying the deterioration information that isrecorded in the information recorded medium in the deteriorationcorrection data storage unit.

In the measurement instrument, it is preferable that plural points inthe deterioration correction data table are at equal time intervals.

In the measurement instrument, it is preferable that the larger thechanging rate of the deterioration index is, the shorter the timeintervals of the plural points in the deterioration correction datatable are, and the smaller the changing rate of the deterioration indexis, the longer the time intervals of the plural points in thedeterioration correction data table are. According to thisconfiguration, in the case where the deterioration index changesnon-linearly, it is possible to calculate the deterioration index at themeasurement date exactly.

In the measurement instrument, it is preferable that a reagent cartridgeformed by filling a liquid reagent in accordance with the items to bemeasured in a container and sealing the container or a test piece isused as the reagent carrier.

In order to achieve the above-mentioned object, the first reagentcarrier of the present invention is used for the above-mentionedmeasurement instrument and is a reagent cartridge formed by filling aliquid reagent in accordance with the items to be measured in acontainer and sealing the container. To the reagent cartridge, aninformation indicator, in which reagent information necessary todesignate the lot and the date of manufacture is recorded, is attached.

Furthermore, the second reagent carrier of the present invention is atest piece to which an information indicator, in which reagentinformation including information necessary to designate the lot and thedate of manufacture, is attached.

According to these reagent carriers, since the lot information of thereagent carrier is read out from the reagent information indicator ofthe reagent carrier, a user of the measurement instrument is notrequired to carry out operations for inputting the lot information inthe measurement instrument.

In the first or the second reagent carrier, it is preferable that theinformation indicator is an indicator that can be read out optically.

In order to achieve the above-mentioned object, the first informationrecorded medium of the present invention is used for measurementinstrument. In the first information recorded medium, as thedeterioration information of each lot of the reagent informationcarrier, a differential data table showing the difference between thedeterioration index at each point and the deterioration index at thepreceding point of the point with respect to plural points from the dateof manufacture to the expiration date is recorded.

Thus, as compared with the case where the deterioration correction datatable itself is recorded as the deterioration information, it isadvantageous that the volume of the deterioration information to berecorded in the information recorded medium may be small.

In order to achieve the above-mentioned object, the second informationrecorded medium of the present invention is used. In the secondinformation recorded medium, as the deterioration information of eachlot of the reagent carrier, the deterioration correction date tableitself is recorded.

Thus, since the measurement instrument may copy the deteriorationcorrection data table recorded in the information recorded medium in thedeterioration correction data storage unit, it is advantageous that theprocessing block, etc. for forming the deterioration correction datatable is not necessary.

It is preferable that the above-mentioned information recorded medium isany one of a magnetically recorded medium in which the deteriorationinformation is a magnetically recorded, a magneto-optically recordedmedium in which the deterioration information is magneto-opticallyrecorded, and the deterioration information is recorded in a state inwhich it can be read out optically.

Furthermore, in order to achieve the above mentioned object, a method ofthe present invention corrects measurement data for carrying out acorrection in accordance with the deterioration of a reagent over timewith respect to the measurement data measured by using a reagent carrierthat carries a reagent in accordance with items to be measured. To thereagent carrier, an information indicator, in which reagent informationincluding information necessary to designate the lot and the date ofmanufacture is recorded, is attached. The method includes: designating adeterioration correction data table corresponding to the lot of thereagent carrier used for measurement in the deterioration correctiondata table showing the situation of the deterioration of a reagent overtime from the date of manufacture to the expiration date by thedeterioration indices at plural points on a time series for each lot ofthe reagent carrier based on the reagent information obtained from theinformation indicator of the reagent carrier used for measurement,extracting the deterioration indices at the preceding point and thefollowing point of the measurement date of the measurement data in thedeterioration indices recorded in the designated deteriorationcorrection data table, calculating the deterioration index byinterpolation at the measurement date based on the deterioration indicesat the two extracted points, and carrying out the deteriorationcorrection of the measurement data based on the calculated deteriorationindex.

According to this method, by referring to the deterioration correctiondata table in which the situation of the deterioration of a reagent overtime from the date of manufacture to the expiration date is shown on atime series by the deterioration indices at plural times, thedeterioration index at measurement time by interpolation from thedeterioration indices at two consecutive points corresponding to thepreceding and the following points of the measurement date. Based on thecalculated deterioration indices, the deterioration of the measurementdate is corrected.

Thus, even if the deterioration index over time changes curvedly, it ispossible to calculate the deterioration index of the reagent at themeasurement date exactly. Furthermore, since the deteriorationcorrection data table is provided for each lot of the reagent carrier,it is possible to solve the difference of the reagent sensitivity, etc.between lots. As a result, it is possible to obtain adequately correctedmeasurement data in accordance with the deterioration over time and thedifference between lots of the reagent without the need for thecalibration before measurement.

In the above-mentioned method for measuring data, it is preferable thatthe process of calculating the deterioration index by interpolation atthe measurement date includes: deriving the deterioration indexcalculation expression, which satisfies the deterioration indices at thetwo points based on an earlier point of the two points, calculating thenumber of days from the earlier point of the two points to themeasurement date, and substituting the number of days into thedeterioration index calculation expression, thereby calculating thedeterioration index at the measurement date.

Thus, it is possible to calculate the deterioration index at themeasurement date by using the deterioration index calculation expressionapproximately showing the change of the deterioration index for arelatively short time including the measurement date.

Furthermore, it is preferable that the deterioration index calculationexpression is a linear expression. Thus, it is possible to derive thedeterioration index calculation expression by a simple calculation.

In the method for correcting the measurement data, it is preferable thatan information recorded medium in which the deterioration informationrepresenting the situation of the deterioration of a reagent over timefrom the date of manufacture to the expiration date for each lot isformed, and before measurement, the deterioration information is readfrom the information recorded medium, and the deterioration correctiondata table is formed based on the read deterioration information.

Thus, information necessary to form the deterioration correction datatable for each lot of the reagent carrier is available via theinformation recorded medium from, for example a maker, etc. of a reagentcarrier via the information recorded medium.

Furthermore, in order to achieve the above-mentioned object, accordingto the program recorded medium of the present invention, a program forcontrolling the operation for carrying out the deterioration correctionof the measurement data in accordance with the deterioration over timeof a reagent used for measurement in a measurement instrument forcarrying out a measurement by using a reagent carrier that carries areagent in accordance with items to be measured is recorded. To thereagent carrier, an information indicator, in which a reagentinformation including information necessary to designate the lot and thedate of manufacture is recorded, is attached. The program includesdesignating a deterioration correction data table corresponding to thelot of the reagent carrier used for measurement by referring to thedeterioration correction data table storage unit storing thedeterioration correction data table showing the situation of thedeterioration of a reagent over time from the date of manufacture to theexpiration date for each lot of the reagent carrier as the deteriorationindices at plural points on a time series based on the reagentinformation obtained from the information indicator of the reagentcarrier used for measurement, extracting the deterioration indices atthe preceding point and the following point of the measurement date ofthe measurement data in the deterioration indices recorded in thedesignated deterioration correction data table, calculating thedeterioration index by interpolation at the measurement date based onthe deterioration indices at the two extracted points, and executing acorrection calculation of the measurement data based on the calculateddeterioration index.

Thus, it is possible to realize the measurement instrument capable ofappropriately carrying out the deterioration correction of themeasurement data in accordance with the deterioration of the reagentused for measurement over time and the difference between the lots byallowing the CPU etc. to execute the recorded program.

In the above-mentioned program recorded medium, it is preferable thatthe process of calculating the deterioration index by interpolation atthe measurement date includes: deriving a deterioration indexcalculation expression, which satisfies the deterioration indices at thetwo points based on an earlier point of the two points, calculating thenumber of days from the earlier point of the two points to themeasurement date, and substituting the number of days into thedeterioration index calculation expression, thereby calculating thedeterioration index at the measurement date.

Thus, it is possible to calculate the deterioration index at themeasurement date by using the deterioration calculating expression forrepresenting the change of the deterioration index for a relativelyshort time including the measurement date approximately.

Furthermore, it is preferable that the deterioration index calculationexpression is a linear expression. Thus, it is possible to derive thedeterioration index calculation expression by a simple calculation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a configuration of a measurementinstrument according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a reagentcartridge as one example of a reagent carrier used at the time ofmeasurement with the measurement instrument.

FIG. 3 is a perspective view showing a configuration of the reagentcartridge shown in FIG. 2.

FIG. 4 is a flow chart showing procedures of a main process of themeasurement instrument.

FIG. 5 is a flow chart showing detailed procedures of a deteriorationcorrection data registering process in the step S5 of theabove-mentioned main process.

FIG. 6 is a flow chart showing detailed procedures of a measurementexecuting process in the step S4 of the above-mentioned main process.

FIG. 7 is a flow chart showing detailed procedures of a correctioncalculation process in the step S47 of the above-mentioned measurementexecuting process.

BEST MODE OF CARRYING OUT THE INVENTION

Hereinafter, one embodiment of the present invention will be explainedwith reference to the drawings.

The measurement instrument according to this embodiment uses a reagentcartridge (reagent carrier) in which liquid reagent, etc. necessary formeasurement was dispensed in advance. The measurement instrument, afterthe reagent cartridge in which a specimen such as human blood, urine,etc. is filled is provided, carries out all the operations necessary formeasurement in the reagent cartridge so as to form a test sample. Theoperations include, for example, diluting the specimen, stirring/mixingthe specimen and the reagent, and the like. Then, the obtained testsample transmits light with a predetermined wavelength and the lightabsorption (absorbance) is measured. Thus, a simple measurement iscarried out.

Firstly, the reagent cartridge used in the measurement instrument willbe explained.

FIG. 2 is a cross-sectional view and FIG. 3 is a perspective view,respectively showing the configuration of a reagent cartridge used inthe measurement instrument. As shown in FIG. 2, the reagent cartridgeused in the measurement instrument includes a plurality of wells 21 to26, a plurality of cells A to C, a specimen container holder 27, aspecimen chamber 28, and a waste chamber 29.

A material for the container part of the reagent cartridge is notparticularly limited except that a transparent material is used for atleast a part that transmits light when the absorbance is measured.However, it is preferable to use, for example, polystyrene resin etc.from the viewpoint of production management and cost.

In the specimen chamber 28, in preparation for measurement, a specimenis filled in by a pipet etc. In the specimen container holder 27, aspecimen necessary to be centrifuged that is filled and centrifuged canbe set. In the specimen chamber 28, a specimen that is not necessary tobe centrifuged (for example, whole blood, etc.) also can be filled andmeasured.

The waste chamber 29 is a chamber in which a waste liquid is stored, butwhen the reagent cartridge is shipped, a tip 30 used at the time ofmeasurement is accommodated therein. The tip 30 is removed from thewaste chamber 29 in preparation for measurement and is attached to thetip of a nozzle (mentioned below) of the measurement instrument. The tip30 has a function of sucking/draining a specimen, reagent, and the like,by the operation of a sampling pump unit (mentioned below) of themeasurement instrument.

In the wells 21 to 26 and the cells A to C, a liquid reagent, a dilutionsolution and a washing solution, etc. are dispensed in accordance withthe items to be measured. Note here that in the reagent cartridge, asshown in FIG. 3, a reagent etc. in accordance with the items to bemeasured is filled in the wells or the cells in advance so that themeasurement can be carried out with respect to the specific items to bemeasured, and thereafter the reagent cartridge is sealed by attaching aseal 31 on the upper surface of a pack.

Furthermore, on the surface of the seal 31, a bar code 32 is attached tothe side of the open parts of the wells 21 to 26 and the cells A to C.The bar code 32 includes information such as the item number to bemeasured, the reagent cartridge number, the lot number, the date ofmanufacture, the expiration date, and the like, as the informationconcerning the reagent cartridge (reagent information). Note here thebar code 32 may include information other than the above as long as itis within the range of the amount that can be recorded in the bar code32.

Next, a configuration of the measurement instrument according to theembodiment will be explained.

FIG. 1 is a block diagram showing a configuration of the measurementinstrument. The measurement instrument includes a centralcalculating/processing unit (CPU) 1, a ROM 2, a RAM 3, a sheet key 4 fora user to input operation indication, etc., an LCD display 5 made ofliquid crystal display, a printer 6 for printing out measurementresults, etc., an input/output control unit 7 realized by acommunication interface, for example, RS-232C, etc., a magnetic cardreader 8 (information reading unit), a sampling pump unit 9, a nozzledrive unit 10, a measurement unit 11, and a clock 12 (a measurement dateobtaining unit) for obtaining the measurement time.

In the ROM 2, a program etc. for controlling the operation of themeasurement instrument is stored. An example of the stored programincludes, for example, a measurement controlling program for controllingthe measurement operation of the measurement instrument, a deteriorationcorrection date registering program for registering the deteriorationcorrection data in the measurement instrument, and a deteriorationcorrection calculating program for carrying out the correction inaccordance with the deterioration of a reagent over time with respect tothe measured data (deterioration correction), and the like.

The RAM 3 includes a measurement conditions storage unit 3 a for storingvarious conditions concerning the measurement for each item to bemeasured, and a deterioration correction data storage unit 3 b forstoring the deterioration correction data table, etc. of the reagentcartridge used in the measurement instrument. The correctiondeterioration data table numerically represents the reagent sensitivityfor a manufacturing lot of the reagent cartridge used for each item tobe measured every time a predetermined term (for example, one month) haspassed since the lots were manufactured.

Note here that the data of the deterioration correction data table aresupplied by a maker etc. of reagent cartridges. For example, a maker ofreagent cartridges forms data representing the change over time of thereagent sensitivity for each lot of the reagent cartridge; records thedata in a magnetic card; attaches the magnetic card on the reagentcartridge; and then ships the reagent cartridge. A user of themeasurement instrument can register the deterioration correction datatable about a newly purchased reagent cartridge in the RAM 3 by allowingthe magnetic card reader 8 to read the data recorded in the magneticcard attached to the purchased reagent cartridge. This registeringprocess of this deterioration correction data table will be explained indetail later.

The sampling pump unit 9 includes a pump and controls the sucking anddraining of a specimen, a reagent, and the like, via the tip 30 attachedto the tip part of the nozzle of the nozzle drive unit 10 by theoperation of this pump under the control of the CPU 1. The nozzle driveunit 10 controls the operation of the nozzle on the reagent cartridgeunder the control of the CPU 1.

The nozzle of the nozzle drive unit 10 also functions for opening theseal 31 of the reagent cartridge when the reagent cartridge is set inthe measurement instrument and the measurement starts. This nozzle isformed of, for example, stainless steel, etc. and can perforate the seal31. The nozzle drive unit 10 perforates the seal 31 at the open partsuch as wells, cells, and the like, necessary for measurement like this;then inserts the nozzle tip part into the tip 30 loaded in the wastechamber 29; and pulls it out so as to attach the tip 30 to the nozzle.

The CPU 1, for example, transfers the reagent etc. dispensed in thereagent cartridge to the other wells or cells by controlling theoperation of the sampling pump unit 9 and the nozzle drive unit 10 asmentioned below.

Firstly, the CPU 1 shifts the nozzle of the nozzle drive unit 10horizontally along the upper surface of the reagent cartridge, and thentemporarily stops it on the target well or cell. Subsequently bydropping the nozzle into the well or cell, the tip part of the tip 30attached to the nozzle tip part is allowed to reach a liquid surface ofthe well or cell, and thereafter the sampling pump unit 9 is allowed tocarry out the sucking operation, thus allowing the reagent etc.dispensed in the well or cell to be sucked in the tip 30.

Furthermore, by raising the nozzle from the well or cell, horizontallyshifting the nozzle to the other well or cell, dropping the nozzle intothe well or cell, and then allowing the sampling pump unit 9 to carryout the draining operation. Thus, reagent etc. of one well or cell istransferred to the other well or cell.

Furthermore, a washing solution is dispensed in any one of wells and theoperation of sucking the washing solution from the well to the tip 30and draining into the waste chamber 29 is repeated, and thereby the tip30 can be washed and unnecessary reagent, etc. can be prevented frommixing.

In the measurement instrument, the CPU 1 controls the operation of thesampling pump unit 9 and the nozzle drive unit 10 and transfers apredetermined amount of specimens, reagent or diluted solution, etc.from one well or cell to the other well or cell in accordance with thepredetermined procedure corresponding to the items to be measured,thereby diluting the specimen or mixing it with a reagent and formingthe measurement test sample. In the measurement condition storage unit3a of the RAM 3, the operation procedures in accordance with the itemsto be measured of the sampling pump unit 9 and the nozzle drive unit 10are stored. The CPU 1 refers to them when the measurement is executed.

Furthermore, the nozzle drive unit 10 includes a bar code reader(indicator reading unit) for reading out the bar code 32 of the reagentcartridge. The measurement unit 11 includes a mechanism for fixing thereagent cartridge as well as a container sensor for distinguishingwhether or not the reagent cartridge is set in the mechanism and ameasurement sensor. Note here that as the measurement sensor, it ispossible to use a spectrophotometer etc. for measuring the absorbance ofthe test sample by using light with a predetermined wavelength.

Next, the operation of the measurement instrument will be explained.

FIG. 4 is a flow chart showing procedures of a main process of themeasurement instrument. The measurement instrument displays “Executemeasurement” or “Register deterioration correction data,” etc. as menusof options of the operation mode on an initial menu screen of the LCDdisplay 5 (step S1).

When the operator selects/inputs the above-mentioned “Registerdeterioration correction data” by a sheet key 4, the CPU 1 receives thisselection input (step S2) and starts the operation in the selectedoperation mode (step S3).

In the step S3, when the “Start measurement” is selected, the CPU 1advances the control to the step 4, and executes the measurement usingthe reagent cartridge. On the other hand, when the “Registerdeterioration correction data” is selected in the step 3, the CPU 1advances the control to the step S5 and carries out the process forregistering the deterioration correction data about the reagentcartridge used in the measurement instrument.

When the process of the step S4 or S5 is finished, the CPU 1 outputs amessage indicating that the process was finished on the LCD display 5and the operators responds to this message and inputs a message that themessage was checked by the sheet key 4. The CPU 1 receives this keyentry and returns the control to the step S1 (step S6). Thus, themeasurement instrument displays the initial menu on the screen of theLCD display 5 and returns to a state of waiting for an operator's inputfor selection. The above-mentioned steps S1 to S6 are the main processof the measurement instrument.

Herein, in the process of the step S5 of the main process, that is, inwhich a user of the measurement instrument uses the magnetic cardattached to the purchased reagent cartridge and registers thedeterioration correction data table about the reagent cartridge in theRAM 3, will be explained in detail.

As mentioned above, the reagent cartridge is shipped together with amagnetic card recording data, which are formed by a maker, representingthe change over time of the reagent sensitivity for each lot. The Tablebelow (Table 1) shows one example of data to be recorded in the magneticcard by a maker of the reagent cartridge.

As shown in Table 1, the change over time of the reagent sensitivity foreach lot is recorded in the magnetic card in a form of the differentialdata table representing the amount of deterioration with respect to thereagent sensitivity of the previous month for every one month that haspassed from the date of manufacture to the expiration date of thereagent cartridge, wherein the reagent sensitivity at the date ofmanufacture is made to be 100. Note here that in the example shown inTable 1, the expiration date of the reagent cartridge is 24 mounts fromthe date of manufacture. However, the expiration date can be setarbitrarily in accordance with the types of reagent cartridges, etc.

TABLE 1 A 1 2 3 4 5 6 7 8 9 10 11 12 . . . 23 24 B 0 2 2 1 1 2 1 1 1 1 21 . . . 1 0 A: number of elapsed months B: differential data

Note here that in the magnetic card, together with the differential datatable, information such as names of the items to be measured and itemnumbers corresponding to the names, number of lots corresponding to eachdifferential data table (hereinafter, lot number will be referred to)and the date of manufacture, the number of reagent cartridgemanufactured in the lot, as well as the expiration date of the reagentcartridge, etc. is recorded by a maker.

FIG. 5 shows a process of step S5 in detail. Firstly, the CPU 1 readsout the deterioration correction data registering program from the ROM 2(step S51). The CPU 1 hereafter operates in accordance with thisprogram, and thereby a deterioration correction data registering processis executed.

Next, the CPU 1 displays a message on the LCD display 5 requesting anoperator to insert the magnetic card into the magnetic card reader 8(step S52).

When the operator inserts the magnetic card into the magnetic cardreader 8 in accordance with the above-mentioned message, the magneticcard reader 8 reads out the information recorded in the magnetic card(step S53). Note here that the information read out herein includes, asmentioned above, the differential data table recorded for each lot ofthe reagent cartridge, the names of items to be measured and itemnumbers corresponding to the names, the lot number corresponding to eachdifferential data table and the date of manufacture, the reagentcartridge number manufactured in the lot, as well as the expiration dateof the reagent cartridge of the lots, etc.

The CPU 1 analyzes the information read out by the magnetic card reader8 and allows it to be stored in a predetermined region of the RAM 3(step S54). Note here that the CPU 1 does not record the differentialdata table read out by the magnetic card as it is but forms thedeterioration correction data table to be stored in the RAM 3 bycalculating the sensitivity D_(m) of the reagent after m months havepassed since the date of manufacture from the following expression(Formula 1) based on the differential data recorded in the differentialdata table. In Formula 1, m denotes the number of elapsed months fromthe date of manufacture, and d_(m) denotes a differential data of thismouth in the differential data table.

$\begin{matrix}{D_{m} = {100 - {\sum\limits_{i = 1}^{m}d_{m}}}} & \left( {{Formula}\mspace{14mu} 1} \right)\end{matrix}$

Thus, in the case where the contents of the differential data table readout by the magnetic card are, for example, the contents shown in Table1, the contents of the deterioration correction data table stored in theRAM 3 become the contents shown in the following table (Table 2).

TABLE 2 A 1 2 3 4 5 6 7 8 9 10 11 12 . . . 23 24 B 100 98 96 95 94 92 9190 89 88 86 85 . . . 81 81 A: number of elapsed months B: reagentsensitivity

Note here that a maker of a reagent cartridge may record thedeterioration correction data table in a magnetic card directly withoutusing the differential data table so that the measurement instrumentregisters the read out deterioration correction data table itself in theRAM 3. However, as mentioned above, it is advantageous that theconfiguration in which the differential data table is recorded in themagnetic card and registered in the measurement instrument whenconverted into the deterioration correction data table, as the volume ofthe information recorded in the magnetic card may be small.

Furthermore, a configuration in which differential data table read outfrom the magnetic card is recorded in the deterioration correction datastorage unit 3 b of the RAM 3 may be employed, which is advantageous inthat the volume of the RAM 3 may be small. On the other hand, accordingto the above-mentioned configuration in which the data are convertedinto the deterioration correction data table and stored in the RAM 3, itis advantageous that a correction calculation after measurement can becarried out at high speed.

When the process of allowing the deterioration correction data table tobe stored in the RAM 3 is finished, the CPU 1 displays a messageindicating that a deterioration correction data registering process wasfinished on the LCD display 5 (step S55) and returns the control to themain process (Return).

As mentioned above, in the measurement instrument, by a simple operationof allowing the magnetic card reader 8 to read out the magnetic cardsupplied by a maker of a reagent cartridge, the deterioration correctiondata for each lot of the reagent cartridge can be registered in the RAM3.

Next, the process of the step S4 of the main process of the measurementinstrument, that is, the process for carrying out the measurement byusing the reagent cartridge, will be explained in detail.

As mentioned above, the measurement instrument displays a screen as aninitial menu on the LCD display 5 so that an operator can select theoperation mode of the measurement instrument (step S1 in FIG. 5).Herein, if the operator selects “Start measurement” from the initialmenu and carries out the key entry from the sheet key 4 (step S2, S3), ameasurement executing process of step S4 starts.

As shown in FIG. 6, firstly, the CPU 1 calls the measurement controlprogram for controlling the measurement operation from the ROM 2 (stepS41). The subsequent processes can be executed as the CPU 1 operates inaccordance with this measurement control program. After reading out ofthe program is finished, the CPU 1 displays a message indicating thatthe measurement starts on the LCD display 5.

In accordance with the contents displayed on the LCD display 5, anoperator fills a specimen in the specimen chamber 28 of the reagentcartridge and sets the reagent cartridge in the measurement unit 11. TheCPU 1 recognizes that the reagent cartridge is set in the measurementunit 11 based on ON/OFF signal of the reagent cartridge sensor mountedon the measurement unit 11 (step S42). At this time, in order to preventmisrecognition, the CPU 1 recognizes whether or not the reagentcartridge is rightly set by checking the sensor signal of themeasurement unit 11 twice or more at the predetermined period.

After the CPU 1 can recognize that the reagent cartridge is set, itsends a control command to the nozzle drive unit 10 and allows the barcord reader mounted on the nozzle drive unit 10 to read out the bar code32 of the reagent cartridge set in the measurement unit 11 (step S43).

Then, the CPU 1 checks the bar code information read out by the bar codereader against the information stored in the RAM 3, thereby determiningwhether or not the measurement condition about the reagent cartridge isstored in the RAM 3 (step S44).

That is, as mentioned above, the bar code 32 of the reagent cartridgeincludes the information such as the names of the items to be measured,the number of the items to be measured, the lot number of the reagentcartridge, the date of manufacture, the reagent cartridge number, theexpiration date, and the like, of the reagent cartridge. Therefore, theCPU 1 retrieves the measurement condition storage unit 3 a of the RAM 3by using the number of items to be measured read out by the bar code 32as a retrieving key.

Consequently, in the case where the measurement condition including thenumber of the items to be measured that coincides with the retrievingkey is stored in the measurement condition storage unit 3 a of the RAM 3(in the case of YES in step S44), the CPU 1 reads out the measurementcondition of the item to be measured and parameter-inputs it into themeasurement control program that was already read out in the step S41(step S45).

Then, the CPU 1 displays a message indicating that the measurementoperation starts on the LCD display 5 and controls the sampling pumpunit 9 and the nozzle drive unit 10 in accordance with the measurementcontrol program, thereby carrying out the measurement of the items to bemeasured (step S46). When the measurement is finished, a correctioncalculation process of the measurement results is carried out based onthe deterioration correction data of the reagent cartridge stored in thedeterioration correction data table of the RAM 3 (step S47) and thenoutputs the calculation results to the LCD display 5, a printer 6 or aninput/output control unit 7 (step S48).

Then, when an operator removes the used reagent cartridge from themeasurement unit 11, the CPU 1 recognizes that the reagent cartridge isremoved based on the sensor signal of the measurement unit 11 andreturns to the main process shown in the flow chart of FIG. 4.

On the other hand, as a result of the checking process of the step S44,in the case where the measurement conditions including the number of theitems to be measured and the expiration date that coincides with theretrieving key are not stored in the measurement condition storage unit3 a of the RAM 3 (in the case of NO in step S44), the CPU 1 displays amessage indicating that the set reagent cartridge is not registered onthe LCD display 5 (step S49) and returns to the main process shown inthe flow chart of FIG. 4.

Note here that it can be thought that the measurement conditions of thereagent cartridge are also registered in a magnetic card, etc. andsupplied to a user of the measurement instrument. In this case, as instep. S49, in the case where the message indicating that the measurementconditions of the reagent cartridge are not registered is displayed, aconfiguration may be employed, that is, as in the process for readingout the deterioration correction data table from the magnetic card andregistering it in the RAM 3, a process of using the magnetic cardattached to the purchased reagent cartridge, so that the measurementconditions recorded in the magnetic card are stored in the measurementcondition storage unit 3 a of the RAM 3 may be employed.

Herein, the correction calculation process in the step S47 will beexplained in detail with reference to FIG. 7.

This correction calculating process is controlled by the deteriorationcorrection calculating program to be called as a sub routine from themeasurement control program for controlling a series of processes ofsteps S41 to S49 of FIG. 6. That is, after the basic calculations of themeasurement and the measurement results in the step S46 shown in FIG. 6are finished, the CPU 1 reads out the deterioration correctioncalculating program from the ROM 2, and takes the number of the items tobe measured, the number of the reagent cartridge used for measurement,the date of manufacture and the lot number, as the parameter, from themeasurement control program to the deterioration correction calculatingprogram and starts the execution of the deterioration correctioncalculating program (step S471 of FIG. 7).

Next, the CPU 1 obtains the expiration date of the reagent cartridgeused for measurement by retrieving the deterioration correction datastorage unit 3 b of the RAM 3 by using the number of the items to bemeasured, the number of the reagent cartridge and the lot number as aretrieving key (step S472).

The CPU 1 determines whether or not the measurement is carried outwithin the expiration date of the reagent cartridge based on themeasurement date obtained from the clock 12 and the deteriorationcorrection data table extracted from the step S473 (step S473). In thecase where the measurement is past the expiration date (in the case ofNO in step S473), the CPU 1 outputs a warning message on the LCD display5 and the printer 6, and returns to the measurement control program(step S480).

On the other hand, in the case where the measurement date is within theexpiration date (in the case of YES in step S473), the CPU 1 comparesthe measurement date with the date of manufacture of the lot, therebycalculating the number of elapsed days from the date of manufacture ofthe reagent cartridge to the measurement date (step S474).

Next, the CPU 1 retrieves the deterioration correction data storage unit3 b of the RAM 3 by using the number of the items to be measured, thenumber of a reagent cartridge and the lot number as a retrieving key,and thereby reading out the deterioration correction data table of thereagent cartridge used for measurement (step S475).

Then, the CPU 1 extracts data of two points corresponding to rightbefore and right after the elapsed days calculated in the step S474 fromthe deterioration correction data table read out in the step S475 (stepS476). In the case where the elapsed days from the manufacturing date tothe measurement date is, for example, 2.5 months, the reagentsensitivity at the second month and the third month are extracted fromthe deterioration correction table as the data at two points.

The CPU 1 obtains the deterioration index calculation expression for onemonth between two points as a linear expression from the extracted dataat two points (step S477). That is, when the data at two pointsextracted in the step S476 are the data of the m₁ -th month and them₂-th month (m₁<m₂) and the reagent sensitivities at respective pointsare D_(m1) and D_(m2), the deterioration index calculation expressionbecomes as the following formula (Formula 2). Note here that in thedeterioration index calculation expression, X denotes elapsed time(unit: month) from the m₁-th month to the measurement date, and Ydenotes the reagent sensitivity at the measurement date.

$\begin{matrix}{Y = {{\frac{D_{m2} - D_{m1}}{m_{2} - m_{1}}X} + D_{m1}}} & \left( {{Formula}\mspace{14mu} 2} \right)\end{matrix}$

Furthermore, the CPU 1 obtains the elapsed time from the m₁-th month tothe measurement date and inputs it into X of the deterioration indexcalculation expression obtained in the step S477 and obtains the reagentsensitivity Y (step S478). In the case where the elapsed time from themanufacturing date to the measurement date is, for example, 2.5 months,0.5 months as an elapsed time from the second month to the measurementdate is input into X in the deterioration index calculation expression(Formula 2) in which m₁ is 2 and m₂ is 3 to obtain the reagentsensitivity at the measurement date. Herein, in the case of thedeterioration correction data table shown in, for example, Table 2,since D_(m1) is 98 and D_(m2) is 96, the value of the reagentsensitivity Y on the measurement date (2.5th month from the date ofmanufacture) is 97 from the Formula 2.

The CPU 1 corrects the measurement data based on the reagent sensitivityY obtained in the step S478 (step S479). That is, by multiplying 100/Yto the measurement value, the appropriate measurement value, in whichthe reduction of the reagent sensitivity due to the deterioration of thereagent over time is corrected, can be obtained.

Thereafter, the CPU 1 returns the measurement value after the correctionto the measurement control program and at the same time returns thecontrol (Return).

As mentioned above, according to the steps S471 to S490 shown in FIG. 7,the deterioration correction calculating process of the measurementvalue in the step S47 in FIG. 6 can be realized.

Note here that this embodiment discloses the case where when thedeterioration index calculation expression is derived in the step S477,a linear expression is obtained from two points extracted in the stepS476. However, the deterioration index calculation expression is notnecessarily limited to a linear expression and various kinds ofinterpolation expressions can be used.

Note here that the differential data table shown in Table 1 anddeterioration correction data table shown in Table 2 represent thevariation of the reagent sensitivity for each constant period (onemonth) from the date of manufacture of the reagent cartridge. The lengthof the time is not necessarily limited to one month and further it isnot always constant intervals. For example, in the case where thereagent sensitivity changes non-linearly, etc., the deteriorationcorrection data table may be used so that in the period in which thechange of the reagent sensitivity is gentle, the interval is long (forexample, two months) and in the period in which the change of thereagent sensitivity is steep, the interval is short (for example, oneweek). Thus, it is advantageous that more adequate correction inaccordance with the deterioration of the reagent can be carried out andat the same time it is possible to use the capacity of the RAM 3effectively.

Furthermore, as an example of the deterioration index to be recorded inthe deterioration correction data table, this embodiment discloses thenumerically represented reagent sensitivity for every one month that haspassed with respect to the reagent sensitivity at the date ofmanufacture of 100. However, it is possible to use the other numericvalues as the deterioration index.

Furthermore, as an example of the combination of the informationindicator attached to the reagent cartridge and the indicator readingunit for reading this indicator, this embodiment shows the bar code 32and a bar code reader of the nozzle drive unit 10. However, thecombination of the information indicator and the indicator reading meansis not necessarily limited to this. Any combination of an indicator thatcan include information concerning a cartridge (reagent information) andan instrument that can read out the information can employ an indicatorrecorded by an optical means or magnetic means, and other arbitrarymeans and a reading instrument thereof. The following are some of theother specific examples. For example, a combination of an informationindicator magnetically recorded in a reagent cartridge and a means formagnetically reading out this information indicator into the nozzledrive unit 10 may be employed. Furthermore, a configuration in whichprinted characters are used as the information indicator and the printedcharacters are read out by an OCR scanner can be employed. Alternately,an IC chip is used as the information indicator, and the measurementinstrument may be provided with an IC chip reader.

Furthermore, this embodiment shows an example in which information suchas the lot number and the date of manufacture of the reagent cartridgedirectly is included in the bar code 32 of the reagent cartridge.However, the lot number and the date of manufacture may not necessarilybe included directly in the bar code 32 of the reagent cartridge if thelot and date of manufacture of each reagent cartridge can be designatedby comparing the other information, for example, a reagent cartridgenumber, etc. with the information stored in the deterioration correctiondata storage unit 3 b of the RAM 3.

Furthermore, in the above-mentioned explanation, the example where thereagent cartridge in which the liquid reagent is filled in as thereagent carrier was explained in detail. However, as the reagentcarrier, a filter paper or resin sheet, etc. which is impregnated with areagent or a test piece formed by a reagent layer on the base materialmay be used.

INDUSTRIAL APPLICABILITY

As mentioned above, according to the measurement instrument of thepresent invention, a deterioration index representing the deteriorationof a reagent over time can be calculated by interpolation based on thedeterioration correction data table prepared for each lot, even in thecase where the deterioration index changes non-linearly, it is possibleto calculate the deterioration index at the date of the measurementexactly and at the same time, the difference between lots adequately. Asa result, it is possible to provide a measurement instrument capable ofobtaining the measurement data which is corrected adequately inaccordance with the deterioration of the reagent over time and thedifference between lots without calibration before measurement.

1. A measurement instrument that carries out a measurement of a reagentin accordance with items to be measured and that carries out adeterioration correction of measurement data in accordance withdeterioration of the reagent used for measurement over time, themeasurement instrument comprising: a reagent carrier that carries areagent in accordance with items to be measured; an informationindicator, in which reagent information including information necessaryto designate a lot and a date of manufacture is recorded, being attachedto the reagent carrier; a deterioration correction data storage unitthat stores a deterioration correction data table containingdeterioration indices showing a deterioration over time from the date ofmanufacture to an expiration date at plural time points on a time seriesfor each lot of the reagent carrier; an indicator reading unit thatreads the reagent information from the information indicator attached tothe reagent carrier to be measured; a measurement date obtaining unitthat obtains a measurement date when the measurement is executed; and ameasurement controlling unit that designates the deteriorationcorrection data table corresponding to the lot of the reagent carrier tobe measured with reference to the deterioration correction data storageunit based on the reagent information read by the indicator readingunit, calculates a deterioration index by interpolation at themeasurement date based on the deterioration indices at a preceding timepoint and a following time point of the measurement date amongdeterioration indices recorded in the designated deteriorationcorrection data table, and carries out a deterioration correction of themeasurement data based on the calculated deterioration index.
 2. Themeasurement instrument according to claim 1, wherein the measurementcontrolling unit derives a deterioration index calculating expressionthat satisfies the deterioration indices at the preceding time point andthe following time point based on an earlier time point of the precedingtime point and the following time point, calculates a number of daysfrom the earlier time point of the preceding time point and thefollowing time point to the measurement date, and substitutes the numberof days in the deterioration index calculation expression, therebycalculating the deterioration index at the measurement date.
 3. Themeasurement instrument according to claim 2, wherein the deteriorationindex calculation expression is a linear expression.
 4. The measurementinstrument according to claim 1, further comprising an informationreading unit that reads the deterioration indices to be stored in thedeterioration correction data table from an information recorded medium,wherein the measurement instrument generates the deteriorationcorrection data table based on the deterioration indices read from theinformation recorded medium, and stores the deterioration correctiondata table in the deterioration correction data storage unit.
 5. Themeasurement instrument according to claim 4, wherein as thedeterioration information of each lot of the reagent carrier, adifferential data table showing the difference between the deteriorationindex at each time point and the deterioration index at the precedingtime point with respect to plural time points from the date ofmanufacture to the expiration date is recorded on the informationrecorded medium.
 6. The measurement instrument according to claim 5,wherein the information recorded medium is a magnetically recordedmedium in which the deterioration information is magnetically recorded.7. The measurement instrument according to claim 5, wherein theinformation recorded medium is a magneto-optically recorded medium inwhich the deterioration information is magneto-optically recorded. 8.The measurement instrument according to claim 5, wherein thedeterioration information is recorded in a state in which it can be readout optically from the information recorded medium.
 9. The measurementinstrument according to claim 4, wherein as the deteriorationinformation of each lot of the reagent carrier, the deteriorationcorrection data table itself is recorded on the information recordedmedium.
 10. The measurement instrument according to claim 1, furthercomprising an information reading unit that reads a differential datatable showing the difference between the deterioration index at eachtime point and the deterioration index at the preceding time point withrespect to plural time points from the date of manufacture to theexpiration date.
 11. The measurement instrument according to claim 1,further comprising an information reading unit that reads thedeterioration correction data table from an information recorded medium,wherein the measurement instrument stores the deterioration correctiondata table in the deterioration correction data storage unit.
 12. Themeasurement instrument according to claim 1, wherein the plural timepoints in the deterioration correction data table are at equal timeintervals.
 13. The measurement instrument according to claim 1, whereinthe larger a rate of change of the deterioration index is, the shorterthe time intervals of the plural time points in the deteriorationcorrection data table are, and the smaller the a rate of change of thedeterioration index is, the longer the time intervals of the plural timepoints in the deterioration correction data table are.
 14. Themeasurement instrument according to claim 1, wherein a reagent cartridgeformed by filling a liquid reagent in accordance with the items to bemeasured in a container and sealing the container is used as the reagentcarrier.
 15. The measurement instrument according to claim 1, wherein atest piece is used as the reagent carrier.
 16. A reagent carrier usedfor the measurement instrument according to claim 1, wherein the reagentcarrier is formed by filling a liquid reagent in accordance with theitems to be measured in a container and sealing the container and towhich an information indicator, in which reagent information necessaryto designate the lot and the date of manufacture is recorded, isattached.
 17. The reagent carrier according to claim 16, wherein theinformation indicator is an indicator that can be read out optically.18. A reagent carrier used for the measurement instrument according toclaim 1, wherein the reagent carrier is a test piece to which aninformation indicator, in which reagent information includinginformation necessary to designate the lot and the date of manufacture,is attached.